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z8530tty.c revision 1.85
      1 /*	$NetBSD: z8530tty.c,v 1.85 2002/10/23 09:13:19 jdolecek Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1993, 1994, 1995, 1996, 1997, 1998, 1999
      5  *	Charles M. Hannum.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by Charles M. Hannum.
     18  * 4. The name of the author may not be used to endorse or promote products
     19  *    derived from this software without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     22  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     23  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     24  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     26  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     30  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     31  */
     32 
     33 /*
     34  * Copyright (c) 1994 Gordon W. Ross
     35  * Copyright (c) 1992, 1993
     36  *	The Regents of the University of California.  All rights reserved.
     37  *
     38  * This software was developed by the Computer Systems Engineering group
     39  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
     40  * contributed to Berkeley.
     41  *
     42  * All advertising materials mentioning features or use of this software
     43  * must display the following acknowledgement:
     44  *	This product includes software developed by the University of
     45  *	California, Lawrence Berkeley Laboratory.
     46  *
     47  * Redistribution and use in source and binary forms, with or without
     48  * modification, are permitted provided that the following conditions
     49  * are met:
     50  * 1. Redistributions of source code must retain the above copyright
     51  *    notice, this list of conditions and the following disclaimer.
     52  * 2. Redistributions in binary form must reproduce the above copyright
     53  *    notice, this list of conditions and the following disclaimer in the
     54  *    documentation and/or other materials provided with the distribution.
     55  * 3. All advertising materials mentioning features or use of this software
     56  *    must display the following acknowledgement:
     57  *	This product includes software developed by the University of
     58  *	California, Berkeley and its contributors.
     59  * 4. Neither the name of the University nor the names of its contributors
     60  *    may be used to endorse or promote products derived from this software
     61  *    without specific prior written permission.
     62  *
     63  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     64  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     65  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     66  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     67  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     68  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     69  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     70  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     71  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     72  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     73  * SUCH DAMAGE.
     74  *
     75  *	@(#)zs.c	8.1 (Berkeley) 7/19/93
     76  */
     77 
     78 /*
     79  * Zilog Z8530 Dual UART driver (tty interface)
     80  *
     81  * This is the "slave" driver that will be attached to
     82  * the "zsc" driver for plain "tty" async. serial lines.
     83  *
     84  * Credits, history:
     85  *
     86  * The original version of this code was the sparc/dev/zs.c driver
     87  * as distributed with the Berkeley 4.4 Lite release.  Since then,
     88  * Gordon Ross reorganized the code into the current parent/child
     89  * driver scheme, separating the Sun keyboard and mouse support
     90  * into independent child drivers.
     91  *
     92  * RTS/CTS flow-control support was a collaboration of:
     93  *	Gordon Ross <gwr (at) netbsd.org>,
     94  *	Bill Studenmund <wrstuden (at) loki.stanford.edu>
     95  *	Ian Dall <Ian.Dall (at) dsto.defence.gov.au>
     96  *
     97  * The driver was massively overhauled in November 1997 by Charles Hannum,
     98  * fixing *many* bugs, and substantially improving performance.
     99  */
    100 
    101 #include <sys/cdefs.h>
    102 __KERNEL_RCSID(0, "$NetBSD: z8530tty.c,v 1.85 2002/10/23 09:13:19 jdolecek Exp $");
    103 
    104 #include "opt_kgdb.h"
    105 
    106 #include <sys/param.h>
    107 #include <sys/systm.h>
    108 #include <sys/proc.h>
    109 #include <sys/device.h>
    110 #include <sys/conf.h>
    111 #include <sys/file.h>
    112 #include <sys/ioctl.h>
    113 #include <sys/malloc.h>
    114 #include <sys/timepps.h>
    115 #include <sys/tty.h>
    116 #include <sys/time.h>
    117 #include <sys/kernel.h>
    118 #include <sys/syslog.h>
    119 
    120 #include <dev/ic/z8530reg.h>
    121 #include <machine/z8530var.h>
    122 
    123 #include <dev/cons.h>
    124 
    125 #include "locators.h"
    126 
    127 /*
    128  * How many input characters we can buffer.
    129  * The port-specific var.h may override this.
    130  * Note: must be a power of two!
    131  */
    132 #ifndef	ZSTTY_RING_SIZE
    133 #define	ZSTTY_RING_SIZE	2048
    134 #endif
    135 
    136 static struct cnm_state zstty_cnm_state;
    137 /*
    138  * Make this an option variable one can patch.
    139  * But be warned:  this must be a power of 2!
    140  */
    141 u_int zstty_rbuf_size = ZSTTY_RING_SIZE;
    142 
    143 /* Stop input when 3/4 of the ring is full; restart when only 1/4 is full. */
    144 u_int zstty_rbuf_hiwat = (ZSTTY_RING_SIZE * 1) / 4;
    145 u_int zstty_rbuf_lowat = (ZSTTY_RING_SIZE * 3) / 4;
    146 
    147 static int zsppscap =
    148 	PPS_TSFMT_TSPEC |
    149 	PPS_CAPTUREASSERT |
    150 	PPS_CAPTURECLEAR |
    151 #ifdef  PPS_SYNC
    152 	PPS_HARDPPSONASSERT | PPS_HARDPPSONCLEAR |
    153 #endif	/* PPS_SYNC */
    154 	PPS_OFFSETASSERT | PPS_OFFSETCLEAR;
    155 
    156 struct zstty_softc {
    157 	struct	device zst_dev;		/* required first: base device */
    158 	struct  tty *zst_tty;
    159 	struct	zs_chanstate *zst_cs;
    160 
    161 	struct callout zst_diag_ch;
    162 
    163 	u_int zst_overflows,
    164 	      zst_floods,
    165 	      zst_errors;
    166 
    167 	int zst_hwflags,	/* see z8530var.h */
    168 	    zst_swflags;	/* TIOCFLAG_SOFTCAR, ... <ttycom.h> */
    169 
    170 	u_int zst_r_hiwat,
    171 	      zst_r_lowat;
    172 	u_char *volatile zst_rbget,
    173 	       *volatile zst_rbput;
    174 	volatile u_int zst_rbavail;
    175 	u_char *zst_rbuf,
    176 	       *zst_ebuf;
    177 
    178 	/*
    179 	 * The transmit byte count and address are used for pseudo-DMA
    180 	 * output in the hardware interrupt code.  PDMA can be suspended
    181 	 * to get pending changes done; heldtbc is used for this.  It can
    182 	 * also be stopped for ^S; this sets TS_TTSTOP in tp->t_state.
    183 	 */
    184 	u_char *zst_tba;		/* transmit buffer address */
    185 	u_int zst_tbc,			/* transmit byte count */
    186 	      zst_heldtbc;		/* held tbc while xmission stopped */
    187 
    188 	/* Flags to communicate with zstty_softint() */
    189 	volatile u_char zst_rx_flags,	/* receiver blocked */
    190 #define	RX_TTY_BLOCKED		0x01
    191 #define	RX_TTY_OVERFLOWED	0x02
    192 #define	RX_IBUF_BLOCKED		0x04
    193 #define	RX_IBUF_OVERFLOWED	0x08
    194 #define	RX_ANY_BLOCK		0x0f
    195 			zst_tx_busy,	/* working on an output chunk */
    196 			zst_tx_done,	/* done with one output chunk */
    197 			zst_tx_stopped,	/* H/W level stop (lost CTS) */
    198 			zst_st_check,	/* got a status interrupt */
    199 			zst_rx_ready;
    200 
    201 	/* PPS signal on DCD, with or without inkernel clock disciplining */
    202 	u_char  zst_ppsmask;			/* pps signal mask */
    203 	u_char  zst_ppsassert;			/* pps leading edge */
    204 	u_char  zst_ppsclear;			/* pps trailing edge */
    205 	pps_info_t ppsinfo;
    206 	pps_params_t ppsparam;
    207 };
    208 
    209 /* Macros to clear/set/test flags. */
    210 #define SET(t, f)	(t) |= (f)
    211 #define CLR(t, f)	(t) &= ~(f)
    212 #define ISSET(t, f)	((t) & (f))
    213 
    214 /* Definition of the driver for autoconfig. */
    215 static int	zstty_match(struct device *, struct cfdata *, void *);
    216 static void	zstty_attach(struct device *, struct device *, void *);
    217 
    218 CFATTACH_DECL(zstty, sizeof(struct zstty_softc),
    219     zstty_match, zstty_attach, NULL, NULL);
    220 
    221 extern struct cfdriver zstty_cd;
    222 
    223 dev_type_open(zsopen);
    224 dev_type_close(zsclose);
    225 dev_type_read(zsread);
    226 dev_type_write(zswrite);
    227 dev_type_ioctl(zsioctl);
    228 dev_type_stop(zsstop);
    229 dev_type_tty(zstty);
    230 dev_type_poll(zspoll);
    231 
    232 const struct cdevsw zstty_cdevsw = {
    233 	zsopen, zsclose, zsread, zswrite, zsioctl,
    234 	zsstop, zstty, zspoll, nommap, ttykqfilter, D_TTY
    235 };
    236 
    237 struct zsops zsops_tty;
    238 
    239 static void zs_shutdown __P((struct zstty_softc *));
    240 static void	zsstart __P((struct tty *));
    241 static int	zsparam __P((struct tty *, struct termios *));
    242 static void zs_modem __P((struct zstty_softc *, int));
    243 static void tiocm_to_zs __P((struct zstty_softc *, u_long, int));
    244 static int  zs_to_tiocm __P((struct zstty_softc *));
    245 static int    zshwiflow __P((struct tty *, int));
    246 static void  zs_hwiflow __P((struct zstty_softc *));
    247 static void zs_maskintr __P((struct zstty_softc *));
    248 
    249 /* Low-level routines. */
    250 static void zstty_rxint   __P((struct zs_chanstate *));
    251 static void zstty_stint   __P((struct zs_chanstate *, int));
    252 static void zstty_txint   __P((struct zs_chanstate *));
    253 static void zstty_softint __P((struct zs_chanstate *));
    254 
    255 #define	ZSUNIT(x)	(minor(x) & 0x7ffff)
    256 #define	ZSDIALOUT(x)	(minor(x) & 0x80000)
    257 
    258 /*
    259  * zstty_match: how is this zs channel configured?
    260  */
    261 int
    262 zstty_match(parent, cf, aux)
    263 	struct device *parent;
    264 	struct cfdata *cf;
    265 	void   *aux;
    266 {
    267 	struct zsc_attach_args *args = aux;
    268 
    269 	/* Exact match is better than wildcard. */
    270 	if (cf->cf_loc[ZSCCF_CHANNEL] == args->channel)
    271 		return 2;
    272 
    273 	/* This driver accepts wildcard. */
    274 	if (cf->cf_loc[ZSCCF_CHANNEL] == ZSCCF_CHANNEL_DEFAULT)
    275 		return 1;
    276 
    277 	return 0;
    278 }
    279 
    280 void
    281 zstty_attach(parent, self, aux)
    282 	struct device *parent, *self;
    283 	void   *aux;
    284 
    285 {
    286 	struct zsc_softc *zsc = (void *) parent;
    287 	struct zstty_softc *zst = (void *) self;
    288 	struct cfdata *cf = self->dv_cfdata;
    289 	struct zsc_attach_args *args = aux;
    290 	struct zs_chanstate *cs;
    291 	struct tty *tp;
    292 	int channel, s, tty_unit;
    293 	dev_t dev;
    294 	char *i, *o;
    295 
    296 	callout_init(&zst->zst_diag_ch);
    297 	cn_init_magic(&zstty_cnm_state);
    298 
    299 	tty_unit = zst->zst_dev.dv_unit;
    300 	channel = args->channel;
    301 	cs = zsc->zsc_cs[channel];
    302 	cs->cs_private = zst;
    303 	cs->cs_ops = &zsops_tty;
    304 
    305 	zst->zst_cs = cs;
    306 	zst->zst_swflags = cf->cf_flags;	/* softcar, etc. */
    307 	zst->zst_hwflags = args->hwflags;
    308 	dev = makedev(cdevsw_lookup_major(&zstty_cdevsw), tty_unit);
    309 
    310 	if (zst->zst_swflags)
    311 		printf(" flags 0x%x", zst->zst_swflags);
    312 
    313 	/*
    314 	 * Check whether we serve as a console device.
    315 	 * XXX - split console input/output channels aren't
    316 	 *	 supported yet on /dev/console
    317 	 */
    318 	i = o = NULL;
    319 	if ((zst->zst_hwflags & ZS_HWFLAG_CONSOLE_INPUT) != 0) {
    320 		i = "input";
    321 		if ((args->hwflags & ZS_HWFLAG_USE_CONSDEV) != 0) {
    322 			args->consdev->cn_dev = dev;
    323 			cn_tab->cn_pollc = args->consdev->cn_pollc;
    324 			cn_tab->cn_getc = args->consdev->cn_getc;
    325 		}
    326 		cn_tab->cn_dev = dev;
    327 		/* Set console magic to BREAK */
    328 		cn_set_magic("\047\001");
    329 	}
    330 	if ((zst->zst_hwflags & ZS_HWFLAG_CONSOLE_OUTPUT) != 0) {
    331 		o = "output";
    332 		if ((args->hwflags & ZS_HWFLAG_USE_CONSDEV) != 0) {
    333 			cn_tab->cn_putc = args->consdev->cn_putc;
    334 		}
    335 		cn_tab->cn_dev = dev;
    336 	}
    337 	if (i != NULL || o != NULL)
    338 		printf(" (console %s)", i ? (o ? "i/o" : i) : o);
    339 
    340 #ifdef KGDB
    341 	if (zs_check_kgdb(cs, dev)) {
    342 		/*
    343 		 * Allow kgdb to "take over" this port.  Returns true
    344 		 * if this serial port is in-use by kgdb.
    345 		 */
    346 		printf(" (kgdb)\n");
    347 		/*
    348 		 * This is the kgdb port (exclusive use)
    349 		 * so skip the normal attach code.
    350 		 */
    351 		return;
    352 	}
    353 #endif
    354 	printf("\n");
    355 
    356 	tp = ttymalloc();
    357 	tp->t_dev = dev;
    358 	tp->t_oproc = zsstart;
    359 	tp->t_param = zsparam;
    360 	tp->t_hwiflow = zshwiflow;
    361 	tty_attach(tp);
    362 
    363 	zst->zst_tty = tp;
    364 	zst->zst_rbuf = malloc(zstty_rbuf_size << 1, M_DEVBUF, M_WAITOK);
    365 	zst->zst_ebuf = zst->zst_rbuf + (zstty_rbuf_size << 1);
    366 	/* Disable the high water mark. */
    367 	zst->zst_r_hiwat = 0;
    368 	zst->zst_r_lowat = 0;
    369 	zst->zst_rbget = zst->zst_rbput = zst->zst_rbuf;
    370 	zst->zst_rbavail = zstty_rbuf_size;
    371 
    372 	/* if there are no enable/disable functions, assume the device
    373 	   is always enabled */
    374 	if (!cs->enable)
    375 		cs->enabled = 1;
    376 
    377 	/*
    378 	 * Hardware init
    379 	 */
    380 	if (ISSET(zst->zst_hwflags, ZS_HWFLAG_CONSOLE)) {
    381 		/* Call zsparam similar to open. */
    382 		struct termios t;
    383 
    384 		/* Wait a while for previous console output to complete */
    385 		DELAY(10000);
    386 
    387 		/* Setup the "new" parameters in t. */
    388 		t.c_ispeed = 0;
    389 		t.c_ospeed = cs->cs_defspeed;
    390 		t.c_cflag = cs->cs_defcflag;
    391 
    392 		s = splzs();
    393 
    394 		/*
    395 		 * Turn on receiver and status interrupts.
    396 		 * We defer the actual write of the register to zsparam(),
    397 		 * but we must make sure status interrupts are turned on by
    398 		 * the time zsparam() reads the initial rr0 state.
    399 		 */
    400 		SET(cs->cs_preg[1], ZSWR1_RIE | ZSWR1_SIE);
    401 
    402 		splx(s);
    403 
    404 		/* Make sure zsparam will see changes. */
    405 		tp->t_ospeed = 0;
    406 		(void) zsparam(tp, &t);
    407 
    408 		s = splzs();
    409 
    410 		/* Make sure DTR is on now. */
    411 		zs_modem(zst, 1);
    412 
    413 		splx(s);
    414 	} else if (!ISSET(zst->zst_hwflags, ZS_HWFLAG_NORESET)) {
    415 		/* Not the console; may need reset. */
    416 		int reset;
    417 
    418 		reset = (channel == 0) ? ZSWR9_A_RESET : ZSWR9_B_RESET;
    419 
    420 		s = splzs();
    421 
    422 		zs_write_reg(cs, 9, reset);
    423 
    424 		/* Will raise DTR in open. */
    425 		zs_modem(zst, 0);
    426 
    427 		splx(s);
    428 	}
    429 }
    430 
    431 
    432 /*
    433  * Return pointer to our tty.
    434  */
    435 struct tty *
    436 zstty(dev)
    437 	dev_t dev;
    438 {
    439 	struct zstty_softc *zst = device_lookup(&zstty_cd, ZSUNIT(dev));
    440 
    441 	return (zst->zst_tty);
    442 }
    443 
    444 
    445 void
    446 zs_shutdown(zst)
    447 	struct zstty_softc *zst;
    448 {
    449 	struct zs_chanstate *cs = zst->zst_cs;
    450 	struct tty *tp = zst->zst_tty;
    451 	int s;
    452 
    453 	s = splzs();
    454 
    455 	/* If we were asserting flow control, then deassert it. */
    456 	SET(zst->zst_rx_flags, RX_IBUF_BLOCKED);
    457 	zs_hwiflow(zst);
    458 
    459 	/* Clear any break condition set with TIOCSBRK. */
    460 	zs_break(cs, 0);
    461 
    462 	/* Turn off PPS capture on last close. */
    463 	zst->zst_ppsmask = 0;
    464 	zst->ppsparam.mode = 0;
    465 
    466 	/*
    467 	 * Hang up if necessary.  Wait a bit, so the other side has time to
    468 	 * notice even if we immediately open the port again.
    469 	 */
    470 	if (ISSET(tp->t_cflag, HUPCL)) {
    471 		zs_modem(zst, 0);
    472 		(void) tsleep(cs, TTIPRI, ttclos, hz);
    473 	}
    474 
    475 	/* Turn off interrupts if not the console. */
    476 	if (!ISSET(zst->zst_hwflags, ZS_HWFLAG_CONSOLE)) {
    477 		CLR(cs->cs_preg[1], ZSWR1_RIE | ZSWR1_SIE);
    478 		cs->cs_creg[1] = cs->cs_preg[1];
    479 		zs_write_reg(cs, 1, cs->cs_creg[1]);
    480 	}
    481 
    482 	/* Call the power management hook. */
    483 	if (cs->disable) {
    484 #ifdef DIAGNOSTIC
    485 		if (!cs->enabled)
    486 			panic("zs_shutdown: not enabled?");
    487 #endif
    488 		(*cs->disable)(zst->zst_cs);
    489 	}
    490 
    491 	splx(s);
    492 }
    493 
    494 /*
    495  * Open a zs serial (tty) port.
    496  */
    497 int
    498 zsopen(dev, flags, mode, p)
    499 	dev_t dev;
    500 	int flags;
    501 	int mode;
    502 	struct proc *p;
    503 {
    504 	struct zstty_softc *zst;
    505 	struct zs_chanstate *cs;
    506 	struct tty *tp;
    507 	int s, s2;
    508 	int error;
    509 
    510 	zst = device_lookup(&zstty_cd, ZSUNIT(dev));
    511 	if (zst == NULL)
    512 		return (ENXIO);
    513 
    514 	tp = zst->zst_tty;
    515 	cs = zst->zst_cs;
    516 
    517 	/* If KGDB took the line, then tp==NULL */
    518 	if (tp == NULL)
    519 		return (EBUSY);
    520 
    521 	if (ISSET(tp->t_state, TS_ISOPEN) &&
    522 	    ISSET(tp->t_state, TS_XCLUDE) &&
    523 	    p->p_ucred->cr_uid != 0)
    524 		return (EBUSY);
    525 
    526 	s = spltty();
    527 
    528 	/*
    529 	 * Do the following iff this is a first open.
    530 	 */
    531 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
    532 		struct termios t;
    533 
    534 		tp->t_dev = dev;
    535 
    536 		/* Call the power management hook. */
    537 		if (cs->enable) {
    538 			if ((*cs->enable)(cs)) {
    539 				splx(s);
    540 				printf("%s: device enable failed\n",
    541 			       	zst->zst_dev.dv_xname);
    542 				return (EIO);
    543 			}
    544 		}
    545 
    546 		/*
    547 		 * Initialize the termios status to the defaults.  Add in the
    548 		 * sticky bits from TIOCSFLAGS.
    549 		 */
    550 		t.c_ispeed = 0;
    551 		t.c_ospeed = cs->cs_defspeed;
    552 		t.c_cflag = cs->cs_defcflag;
    553 		if (ISSET(zst->zst_swflags, TIOCFLAG_CLOCAL))
    554 			SET(t.c_cflag, CLOCAL);
    555 		if (ISSET(zst->zst_swflags, TIOCFLAG_CRTSCTS))
    556 			SET(t.c_cflag, CRTSCTS);
    557 		if (ISSET(zst->zst_swflags, TIOCFLAG_CDTRCTS))
    558 			SET(t.c_cflag, CDTRCTS);
    559 		if (ISSET(zst->zst_swflags, TIOCFLAG_MDMBUF))
    560 			SET(t.c_cflag, MDMBUF);
    561 
    562 		s2 = splzs();
    563 
    564 		/*
    565 		 * Turn on receiver and status interrupts.
    566 		 * We defer the actual write of the register to zsparam(),
    567 		 * but we must make sure status interrupts are turned on by
    568 		 * the time zsparam() reads the initial rr0 state.
    569 		 */
    570 		SET(cs->cs_preg[1], ZSWR1_RIE | ZSWR1_SIE);
    571 
    572 		/* Clear PPS capture state on first open. */
    573 		zst->zst_ppsmask = 0;
    574 		zst->ppsparam.mode = 0;
    575 
    576 		splx(s2);
    577 
    578 		/* Make sure zsparam will see changes. */
    579 		tp->t_ospeed = 0;
    580 		(void) zsparam(tp, &t);
    581 
    582 		/*
    583 		 * Note: zsparam has done: cflag, ispeed, ospeed
    584 		 * so we just need to do: iflag, oflag, lflag, cc
    585 		 * For "raw" mode, just leave all zeros.
    586 		 */
    587 		if (!ISSET(zst->zst_hwflags, ZS_HWFLAG_RAW)) {
    588 			tp->t_iflag = TTYDEF_IFLAG;
    589 			tp->t_oflag = TTYDEF_OFLAG;
    590 			tp->t_lflag = TTYDEF_LFLAG;
    591 		} else {
    592 			tp->t_iflag = 0;
    593 			tp->t_oflag = 0;
    594 			tp->t_lflag = 0;
    595 		}
    596 		ttychars(tp);
    597 		ttsetwater(tp);
    598 
    599 		s2 = splzs();
    600 
    601 		/*
    602 		 * Turn on DTR.  We must always do this, even if carrier is not
    603 		 * present, because otherwise we'd have to use TIOCSDTR
    604 		 * immediately after setting CLOCAL, which applications do not
    605 		 * expect.  We always assert DTR while the device is open
    606 		 * unless explicitly requested to deassert it.
    607 		 */
    608 		zs_modem(zst, 1);
    609 
    610 		/* Clear the input ring, and unblock. */
    611 		zst->zst_rbget = zst->zst_rbput = zst->zst_rbuf;
    612 		zst->zst_rbavail = zstty_rbuf_size;
    613 		zs_iflush(cs);
    614 		CLR(zst->zst_rx_flags, RX_ANY_BLOCK);
    615 		zs_hwiflow(zst);
    616 
    617 		splx(s2);
    618 	}
    619 
    620 	splx(s);
    621 
    622 	error = ttyopen(tp, ZSDIALOUT(dev), ISSET(flags, O_NONBLOCK));
    623 	if (error)
    624 		goto bad;
    625 
    626 	error = (*tp->t_linesw->l_open)(dev, tp);
    627 	if (error)
    628 		goto bad;
    629 
    630 	return (0);
    631 
    632 bad:
    633 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
    634 		/*
    635 		 * We failed to open the device, and nobody else had it opened.
    636 		 * Clean up the state as appropriate.
    637 		 */
    638 		zs_shutdown(zst);
    639 	}
    640 
    641 	return (error);
    642 }
    643 
    644 /*
    645  * Close a zs serial port.
    646  */
    647 int
    648 zsclose(dev, flags, mode, p)
    649 	dev_t dev;
    650 	int flags;
    651 	int mode;
    652 	struct proc *p;
    653 {
    654 	struct zstty_softc *zst = device_lookup(&zstty_cd, ZSUNIT(dev));
    655 	struct tty *tp = zst->zst_tty;
    656 
    657 	/* XXX This is for cons.c. */
    658 	if (!ISSET(tp->t_state, TS_ISOPEN))
    659 		return 0;
    660 
    661 	(*tp->t_linesw->l_close)(tp, flags);
    662 	ttyclose(tp);
    663 
    664 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
    665 		/*
    666 		 * Although we got a last close, the device may still be in
    667 		 * use; e.g. if this was the dialout node, and there are still
    668 		 * processes waiting for carrier on the non-dialout node.
    669 		 */
    670 		zs_shutdown(zst);
    671 	}
    672 
    673 	return (0);
    674 }
    675 
    676 /*
    677  * Read/write zs serial port.
    678  */
    679 int
    680 zsread(dev, uio, flags)
    681 	dev_t dev;
    682 	struct uio *uio;
    683 	int flags;
    684 {
    685 	struct zstty_softc *zst = device_lookup(&zstty_cd, ZSUNIT(dev));
    686 	struct tty *tp = zst->zst_tty;
    687 
    688 	return ((*tp->t_linesw->l_read)(tp, uio, flags));
    689 }
    690 
    691 int
    692 zswrite(dev, uio, flags)
    693 	dev_t dev;
    694 	struct uio *uio;
    695 	int flags;
    696 {
    697 	struct zstty_softc *zst = device_lookup(&zstty_cd, ZSUNIT(dev));
    698 	struct tty *tp = zst->zst_tty;
    699 
    700 	return ((*tp->t_linesw->l_write)(tp, uio, flags));
    701 }
    702 
    703 int
    704 zspoll(dev, events, p)
    705 	dev_t dev;
    706 	int events;
    707 	struct proc *p;
    708 {
    709 	struct zstty_softc *zst = device_lookup(&zstty_cd, ZSUNIT(dev));
    710 	struct tty *tp = zst->zst_tty;
    711 
    712 	return ((*tp->t_linesw->l_poll)(tp, events, p));
    713 }
    714 
    715 int
    716 zsioctl(dev, cmd, data, flag, p)
    717 	dev_t dev;
    718 	u_long cmd;
    719 	caddr_t data;
    720 	int flag;
    721 	struct proc *p;
    722 {
    723 	struct zstty_softc *zst = device_lookup(&zstty_cd, ZSUNIT(dev));
    724 	struct zs_chanstate *cs = zst->zst_cs;
    725 	struct tty *tp = zst->zst_tty;
    726 	int error;
    727 	int s;
    728 
    729 	error = (*tp->t_linesw->l_ioctl)(tp, cmd, data, flag, p);
    730 	if (error != EPASSTHROUGH)
    731 		return (error);
    732 
    733 	error = ttioctl(tp, cmd, data, flag, p);
    734 	if (error != EPASSTHROUGH)
    735 		return (error);
    736 
    737 #ifdef	ZS_MD_IOCTL
    738 	error = ZS_MD_IOCTL(cs, cmd, data);
    739 	if (error != EPASSTHROUGH)
    740 		return (error);
    741 #endif	/* ZS_MD_IOCTL */
    742 
    743 	error = 0;
    744 
    745 	s = splzs();
    746 
    747 	switch (cmd) {
    748 	case TIOCSBRK:
    749 		zs_break(cs, 1);
    750 		break;
    751 
    752 	case TIOCCBRK:
    753 		zs_break(cs, 0);
    754 		break;
    755 
    756 	case TIOCGFLAGS:
    757 		*(int *)data = zst->zst_swflags;
    758 		break;
    759 
    760 	case TIOCSFLAGS:
    761 		error = suser(p->p_ucred, &p->p_acflag);
    762 		if (error)
    763 			break;
    764 		zst->zst_swflags = *(int *)data;
    765 		break;
    766 
    767 	case TIOCSDTR:
    768 		zs_modem(zst, 1);
    769 		break;
    770 
    771 	case TIOCCDTR:
    772 		zs_modem(zst, 0);
    773 		break;
    774 
    775 	case TIOCMSET:
    776 	case TIOCMBIS:
    777 	case TIOCMBIC:
    778 		tiocm_to_zs(zst, cmd, *(int *)data);
    779 		break;
    780 
    781 	case TIOCMGET:
    782 		*(int *)data = zs_to_tiocm(zst);
    783 		break;
    784 
    785 	case PPS_IOC_CREATE:
    786 		break;
    787 
    788 	case PPS_IOC_DESTROY:
    789 		break;
    790 
    791 	case PPS_IOC_GETPARAMS: {
    792 		pps_params_t *pp;
    793 		pp = (pps_params_t *)data;
    794 		*pp = zst->ppsparam;
    795 		break;
    796 	}
    797 
    798 	case PPS_IOC_SETPARAMS: {
    799 		pps_params_t *pp;
    800 		int mode;
    801 		if (cs->cs_rr0_pps == 0) {
    802 			error = EINVAL;
    803 			break;
    804 		}
    805 		pp = (pps_params_t *)data;
    806 		if (pp->mode & ~zsppscap) {
    807 			error = EINVAL;
    808 			break;
    809 		}
    810 		zst->ppsparam = *pp;
    811 		/*
    812 		 * compute masks from user-specified timestamp state.
    813 		 */
    814 		mode = zst->ppsparam.mode;
    815 #ifdef	PPS_SYNC
    816 		if (mode & PPS_HARDPPSONASSERT) {
    817 			mode |= PPS_CAPTUREASSERT;
    818 			/* XXX revoke any previous HARDPPS source */
    819 		}
    820 		if (mode & PPS_HARDPPSONCLEAR) {
    821 			mode |= PPS_CAPTURECLEAR;
    822 			/* XXX revoke any previous HARDPPS source */
    823 		}
    824 #endif	/* PPS_SYNC */
    825 		switch (mode & PPS_CAPTUREBOTH) {
    826 		case 0:
    827 			zst->zst_ppsmask = 0;
    828 			break;
    829 
    830 		case PPS_CAPTUREASSERT:
    831 			zst->zst_ppsmask = ZSRR0_DCD;
    832 			zst->zst_ppsassert = ZSRR0_DCD;
    833 			zst->zst_ppsclear = -1;
    834 			break;
    835 
    836 		case PPS_CAPTURECLEAR:
    837 			zst->zst_ppsmask = ZSRR0_DCD;
    838 			zst->zst_ppsassert = -1;
    839 			zst->zst_ppsclear = 0;
    840 			break;
    841 
    842 		case PPS_CAPTUREBOTH:
    843 			zst->zst_ppsmask = ZSRR0_DCD;
    844 			zst->zst_ppsassert = ZSRR0_DCD;
    845 			zst->zst_ppsclear = 0;
    846 			break;
    847 
    848 		default:
    849 			error = EINVAL;
    850 			break;
    851 		}
    852 
    853 		/*
    854 		 * Now update interrupts.
    855 		 */
    856 		zs_maskintr(zst);
    857 		/*
    858 		 * If nothing is being transmitted, set up new current values,
    859 		 * else mark them as pending.
    860 		 */
    861 		if (!cs->cs_heldchange) {
    862 			if (zst->zst_tx_busy) {
    863 				zst->zst_heldtbc = zst->zst_tbc;
    864 				zst->zst_tbc = 0;
    865 				cs->cs_heldchange = 1;
    866 			} else
    867 				zs_loadchannelregs(cs);
    868 		}
    869 
    870 		break;
    871 	}
    872 
    873 	case PPS_IOC_GETCAP:
    874 		*(int *)data = zsppscap;
    875 		break;
    876 
    877 	case PPS_IOC_FETCH: {
    878 		pps_info_t *pi;
    879 		pi = (pps_info_t *)data;
    880 		*pi = zst->ppsinfo;
    881 		break;
    882 	}
    883 
    884 	case TIOCDCDTIMESTAMP:	/* XXX old, overloaded  API used by xntpd v3 */
    885 		if (cs->cs_rr0_pps == 0) {
    886 			error = EINVAL;
    887 			break;
    888 		}
    889 		/*
    890 		 * Some GPS clocks models use the falling rather than
    891 		 * rising edge as the on-the-second signal.
    892 		 * The old API has no way to specify PPS polarity.
    893 		 */
    894 		zst->zst_ppsmask = ZSRR0_DCD;
    895 #ifndef	PPS_TRAILING_EDGE
    896 		zst->zst_ppsassert = ZSRR0_DCD;
    897 		zst->zst_ppsclear = -1;
    898 		TIMESPEC_TO_TIMEVAL((struct timeval *)data,
    899 			&zst->ppsinfo.assert_timestamp);
    900 #else
    901 		zst->zst_ppsassert = -1;
    902 		zst->zst_ppsclear = 01;
    903 		TIMESPEC_TO_TIMEVAL((struct timeval *)data,
    904 			&zst->ppsinfo.clear_timestamp);
    905 #endif
    906 		/*
    907 		 * Now update interrupts.
    908 		 */
    909 		zs_maskintr(zst);
    910 		/*
    911 		 * If nothing is being transmitted, set up new current values,
    912 		 * else mark them as pending.
    913 		 */
    914 		if (!cs->cs_heldchange) {
    915 			if (zst->zst_tx_busy) {
    916 				zst->zst_heldtbc = zst->zst_tbc;
    917 				zst->zst_tbc = 0;
    918 				cs->cs_heldchange = 1;
    919 			} else
    920 				zs_loadchannelregs(cs);
    921 		}
    922 
    923 		break;
    924 
    925 	default:
    926 		error = EPASSTHROUGH;
    927 		break;
    928 	}
    929 
    930 	splx(s);
    931 
    932 	return (error);
    933 }
    934 
    935 /*
    936  * Start or restart transmission.
    937  */
    938 static void
    939 zsstart(tp)
    940 	struct tty *tp;
    941 {
    942 	struct zstty_softc *zst = device_lookup(&zstty_cd, ZSUNIT(tp->t_dev));
    943 	struct zs_chanstate *cs = zst->zst_cs;
    944 	int s;
    945 
    946 	s = spltty();
    947 	if (ISSET(tp->t_state, TS_BUSY | TS_TIMEOUT | TS_TTSTOP))
    948 		goto out;
    949 	if (zst->zst_tx_stopped)
    950 		goto out;
    951 
    952 	if (tp->t_outq.c_cc <= tp->t_lowat) {
    953 		if (ISSET(tp->t_state, TS_ASLEEP)) {
    954 			CLR(tp->t_state, TS_ASLEEP);
    955 			wakeup((caddr_t)&tp->t_outq);
    956 		}
    957 		selwakeup(&tp->t_wsel);
    958 		if (tp->t_outq.c_cc == 0)
    959 			goto out;
    960 	}
    961 
    962 	/* Grab the first contiguous region of buffer space. */
    963 	{
    964 		u_char *tba;
    965 		int tbc;
    966 
    967 		tba = tp->t_outq.c_cf;
    968 		tbc = ndqb(&tp->t_outq, 0);
    969 
    970 		(void) splzs();
    971 
    972 		zst->zst_tba = tba;
    973 		zst->zst_tbc = tbc;
    974 	}
    975 
    976 	SET(tp->t_state, TS_BUSY);
    977 	zst->zst_tx_busy = 1;
    978 
    979 	/* Enable transmit completion interrupts if necessary. */
    980 	if (!ISSET(cs->cs_preg[1], ZSWR1_TIE)) {
    981 		SET(cs->cs_preg[1], ZSWR1_TIE);
    982 		cs->cs_creg[1] = cs->cs_preg[1];
    983 		zs_write_reg(cs, 1, cs->cs_creg[1]);
    984 	}
    985 
    986 	/* Output the first character of the contiguous buffer. */
    987 	{
    988 		zs_write_data(cs, *zst->zst_tba);
    989 		zst->zst_tbc--;
    990 		zst->zst_tba++;
    991 	}
    992 out:
    993 	splx(s);
    994 	return;
    995 }
    996 
    997 /*
    998  * Stop output, e.g., for ^S or output flush.
    999  */
   1000 void
   1001 zsstop(tp, flag)
   1002 	struct tty *tp;
   1003 	int flag;
   1004 {
   1005 	struct zstty_softc *zst = device_lookup(&zstty_cd, ZSUNIT(tp->t_dev));
   1006 	int s;
   1007 
   1008 	s = splzs();
   1009 	if (ISSET(tp->t_state, TS_BUSY)) {
   1010 		/* Stop transmitting at the next chunk. */
   1011 		zst->zst_tbc = 0;
   1012 		zst->zst_heldtbc = 0;
   1013 		if (!ISSET(tp->t_state, TS_TTSTOP))
   1014 			SET(tp->t_state, TS_FLUSH);
   1015 	}
   1016 	splx(s);
   1017 }
   1018 
   1019 /*
   1020  * Set ZS tty parameters from termios.
   1021  * XXX - Should just copy the whole termios after
   1022  * making sure all the changes could be done.
   1023  */
   1024 static int
   1025 zsparam(tp, t)
   1026 	struct tty *tp;
   1027 	struct termios *t;
   1028 {
   1029 	struct zstty_softc *zst = device_lookup(&zstty_cd, ZSUNIT(tp->t_dev));
   1030 	struct zs_chanstate *cs = zst->zst_cs;
   1031 	int ospeed, cflag;
   1032 	u_char tmp3, tmp4, tmp5;
   1033 	int s, error;
   1034 
   1035 	ospeed = t->c_ospeed;
   1036 	cflag = t->c_cflag;
   1037 
   1038 	/* Check requested parameters. */
   1039 	if (ospeed < 0)
   1040 		return (EINVAL);
   1041 	if (t->c_ispeed && t->c_ispeed != ospeed)
   1042 		return (EINVAL);
   1043 
   1044 	/*
   1045 	 * For the console, always force CLOCAL and !HUPCL, so that the port
   1046 	 * is always active.
   1047 	 */
   1048 	if (ISSET(zst->zst_swflags, TIOCFLAG_SOFTCAR) ||
   1049 	    ISSET(zst->zst_hwflags, ZS_HWFLAG_CONSOLE)) {
   1050 		SET(cflag, CLOCAL);
   1051 		CLR(cflag, HUPCL);
   1052 	}
   1053 
   1054 	/*
   1055 	 * Only whack the UART when params change.
   1056 	 * Some callers need to clear tp->t_ospeed
   1057 	 * to make sure initialization gets done.
   1058 	 */
   1059 	if (tp->t_ospeed == ospeed &&
   1060 	    tp->t_cflag == cflag)
   1061 		return (0);
   1062 
   1063 	/*
   1064 	 * Call MD functions to deal with changed
   1065 	 * clock modes or H/W flow control modes.
   1066 	 * The BRG divisor is set now. (reg 12,13)
   1067 	 */
   1068 	error = zs_set_speed(cs, ospeed);
   1069 	if (error)
   1070 		return (error);
   1071 	error = zs_set_modes(cs, cflag);
   1072 	if (error)
   1073 		return (error);
   1074 
   1075 	/*
   1076 	 * Block interrupts so that state will not
   1077 	 * be altered until we are done setting it up.
   1078 	 *
   1079 	 * Initial values in cs_preg are set before
   1080 	 * our attach routine is called.  The master
   1081 	 * interrupt enable is handled by zsc.c
   1082 	 *
   1083 	 */
   1084 	s = splzs();
   1085 
   1086 	/*
   1087 	 * Recalculate which status ints to enable.
   1088 	 */
   1089 	zs_maskintr(zst);
   1090 
   1091 	/* Recompute character size bits. */
   1092 	tmp3 = cs->cs_preg[3];
   1093 	tmp5 = cs->cs_preg[5];
   1094 	CLR(tmp3, ZSWR3_RXSIZE);
   1095 	CLR(tmp5, ZSWR5_TXSIZE);
   1096 	switch (ISSET(cflag, CSIZE)) {
   1097 	case CS5:
   1098 		SET(tmp3, ZSWR3_RX_5);
   1099 		SET(tmp5, ZSWR5_TX_5);
   1100 		break;
   1101 	case CS6:
   1102 		SET(tmp3, ZSWR3_RX_6);
   1103 		SET(tmp5, ZSWR5_TX_6);
   1104 		break;
   1105 	case CS7:
   1106 		SET(tmp3, ZSWR3_RX_7);
   1107 		SET(tmp5, ZSWR5_TX_7);
   1108 		break;
   1109 	case CS8:
   1110 		SET(tmp3, ZSWR3_RX_8);
   1111 		SET(tmp5, ZSWR5_TX_8);
   1112 		break;
   1113 	}
   1114 	cs->cs_preg[3] = tmp3;
   1115 	cs->cs_preg[5] = tmp5;
   1116 
   1117 	/*
   1118 	 * Recompute the stop bits and parity bits.  Note that
   1119 	 * zs_set_speed() may have set clock selection bits etc.
   1120 	 * in wr4, so those must preserved.
   1121 	 */
   1122 	tmp4 = cs->cs_preg[4];
   1123 	CLR(tmp4, ZSWR4_SBMASK | ZSWR4_PARMASK);
   1124 	if (ISSET(cflag, CSTOPB))
   1125 		SET(tmp4, ZSWR4_TWOSB);
   1126 	else
   1127 		SET(tmp4, ZSWR4_ONESB);
   1128 	if (!ISSET(cflag, PARODD))
   1129 		SET(tmp4, ZSWR4_EVENP);
   1130 	if (ISSET(cflag, PARENB))
   1131 		SET(tmp4, ZSWR4_PARENB);
   1132 	cs->cs_preg[4] = tmp4;
   1133 
   1134 	/* And copy to tty. */
   1135 	tp->t_ispeed = 0;
   1136 	tp->t_ospeed = ospeed;
   1137 	tp->t_cflag = cflag;
   1138 
   1139 	/*
   1140 	 * If nothing is being transmitted, set up new current values,
   1141 	 * else mark them as pending.
   1142 	 */
   1143 	if (!cs->cs_heldchange) {
   1144 		if (zst->zst_tx_busy) {
   1145 			zst->zst_heldtbc = zst->zst_tbc;
   1146 			zst->zst_tbc = 0;
   1147 			cs->cs_heldchange = 1;
   1148 		} else
   1149 			zs_loadchannelregs(cs);
   1150 	}
   1151 
   1152 	/*
   1153 	 * If hardware flow control is disabled, turn off the buffer water
   1154 	 * marks and unblock any soft flow control state.  Otherwise, enable
   1155 	 * the water marks.
   1156 	 */
   1157 	if (!ISSET(cflag, CHWFLOW)) {
   1158 		zst->zst_r_hiwat = 0;
   1159 		zst->zst_r_lowat = 0;
   1160 		if (ISSET(zst->zst_rx_flags, RX_TTY_OVERFLOWED)) {
   1161 			CLR(zst->zst_rx_flags, RX_TTY_OVERFLOWED);
   1162 			zst->zst_rx_ready = 1;
   1163 			cs->cs_softreq = 1;
   1164 		}
   1165 		if (ISSET(zst->zst_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED)) {
   1166 			CLR(zst->zst_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED);
   1167 			zs_hwiflow(zst);
   1168 		}
   1169 	} else {
   1170 		zst->zst_r_hiwat = zstty_rbuf_hiwat;
   1171 		zst->zst_r_lowat = zstty_rbuf_lowat;
   1172 	}
   1173 
   1174 	/*
   1175 	 * Force a recheck of the hardware carrier and flow control status,
   1176 	 * since we may have changed which bits we're looking at.
   1177 	 */
   1178 	zstty_stint(cs, 1);
   1179 
   1180 	splx(s);
   1181 
   1182 	/*
   1183 	 * If hardware flow control is disabled, unblock any hard flow control
   1184 	 * state.
   1185 	 */
   1186 	if (!ISSET(cflag, CHWFLOW)) {
   1187 		if (zst->zst_tx_stopped) {
   1188 			zst->zst_tx_stopped = 0;
   1189 			zsstart(tp);
   1190 		}
   1191 	}
   1192 
   1193 	zstty_softint(cs);
   1194 
   1195 	return (0);
   1196 }
   1197 
   1198 /*
   1199  * Compute interupt enable bits and set in the pending bits. Called both
   1200  * in zsparam() and when PPS (pulse per second timing) state changes.
   1201  * Must be called at splzs().
   1202  */
   1203 static void
   1204 zs_maskintr(zst)
   1205 	struct zstty_softc *zst;
   1206 {
   1207 	struct zs_chanstate *cs = zst->zst_cs;
   1208 	int tmp15;
   1209 
   1210 	cs->cs_rr0_mask = cs->cs_rr0_cts | cs->cs_rr0_dcd;
   1211 	if (zst->zst_ppsmask != 0)
   1212 		cs->cs_rr0_mask |= cs->cs_rr0_pps;
   1213 	tmp15 = cs->cs_preg[15];
   1214 	if (ISSET(cs->cs_rr0_mask, ZSRR0_DCD))
   1215 		SET(tmp15, ZSWR15_DCD_IE);
   1216 	else
   1217 		CLR(tmp15, ZSWR15_DCD_IE);
   1218 	if (ISSET(cs->cs_rr0_mask, ZSRR0_CTS))
   1219 		SET(tmp15, ZSWR15_CTS_IE);
   1220 	else
   1221 		CLR(tmp15, ZSWR15_CTS_IE);
   1222 	cs->cs_preg[15] = tmp15;
   1223 }
   1224 
   1225 
   1226 /*
   1227  * Raise or lower modem control (DTR/RTS) signals.  If a character is
   1228  * in transmission, the change is deferred.
   1229  */
   1230 static void
   1231 zs_modem(zst, onoff)
   1232 	struct zstty_softc *zst;
   1233 	int onoff;
   1234 {
   1235 	struct zs_chanstate *cs = zst->zst_cs, *ccs;
   1236 
   1237 	if (cs->cs_wr5_dtr == 0)
   1238 		return;
   1239 
   1240 	ccs = (cs->cs_ctl_chan != NULL ? cs->cs_ctl_chan : cs);
   1241 
   1242 	if (onoff)
   1243 		SET(ccs->cs_preg[5], cs->cs_wr5_dtr);
   1244 	else
   1245 		CLR(ccs->cs_preg[5], cs->cs_wr5_dtr);
   1246 
   1247 	if (!cs->cs_heldchange) {
   1248 		if (zst->zst_tx_busy) {
   1249 			zst->zst_heldtbc = zst->zst_tbc;
   1250 			zst->zst_tbc = 0;
   1251 			cs->cs_heldchange = 1;
   1252 		} else
   1253 			zs_loadchannelregs(cs);
   1254 	}
   1255 }
   1256 
   1257 static void
   1258 tiocm_to_zs(zst, how, ttybits)
   1259 	struct zstty_softc *zst;
   1260 	u_long how;
   1261 	int ttybits;
   1262 {
   1263 	struct zs_chanstate *cs = zst->zst_cs, *ccs;
   1264 	u_char zsbits;
   1265 
   1266 	ccs = (cs->cs_ctl_chan != NULL ? cs->cs_ctl_chan : cs);
   1267 
   1268 	zsbits = 0;
   1269 	if (ISSET(ttybits, TIOCM_DTR))
   1270 		SET(zsbits, ZSWR5_DTR);
   1271 	if (ISSET(ttybits, TIOCM_RTS))
   1272 		SET(zsbits, ZSWR5_RTS);
   1273 
   1274 	switch (how) {
   1275 	case TIOCMBIC:
   1276 		CLR(ccs->cs_preg[5], zsbits);
   1277 		break;
   1278 
   1279 	case TIOCMBIS:
   1280 		SET(ccs->cs_preg[5], zsbits);
   1281 		break;
   1282 
   1283 	case TIOCMSET:
   1284 		CLR(ccs->cs_preg[5], ZSWR5_RTS | ZSWR5_DTR);
   1285 		SET(ccs->cs_preg[5], zsbits);
   1286 		break;
   1287 	}
   1288 
   1289 	if (!cs->cs_heldchange) {
   1290 		if (zst->zst_tx_busy) {
   1291 			zst->zst_heldtbc = zst->zst_tbc;
   1292 			zst->zst_tbc = 0;
   1293 			cs->cs_heldchange = 1;
   1294 		} else
   1295 			zs_loadchannelregs(cs);
   1296 	}
   1297 }
   1298 
   1299 static int
   1300 zs_to_tiocm(zst)
   1301 	struct zstty_softc *zst;
   1302 {
   1303 	struct zs_chanstate *cs = zst->zst_cs, *ccs;
   1304 	u_char zsbits;
   1305 	int ttybits = 0;
   1306 
   1307 	ccs = (cs->cs_ctl_chan != NULL ? cs->cs_ctl_chan : cs);
   1308 
   1309 	zsbits = ccs->cs_preg[5];
   1310 	if (ISSET(zsbits, ZSWR5_DTR))
   1311 		SET(ttybits, TIOCM_DTR);
   1312 	if (ISSET(zsbits, ZSWR5_RTS))
   1313 		SET(ttybits, TIOCM_RTS);
   1314 
   1315 	zsbits = cs->cs_rr0;
   1316 	if (ISSET(zsbits, ZSRR0_DCD))
   1317 		SET(ttybits, TIOCM_CD);
   1318 	if (ISSET(zsbits, ZSRR0_CTS))
   1319 		SET(ttybits, TIOCM_CTS);
   1320 
   1321 	return (ttybits);
   1322 }
   1323 
   1324 /*
   1325  * Try to block or unblock input using hardware flow-control.
   1326  * This is called by kern/tty.c if MDMBUF|CRTSCTS is set, and
   1327  * if this function returns non-zero, the TS_TBLOCK flag will
   1328  * be set or cleared according to the "block" arg passed.
   1329  */
   1330 int
   1331 zshwiflow(tp, block)
   1332 	struct tty *tp;
   1333 	int block;
   1334 {
   1335 	struct zstty_softc *zst = device_lookup(&zstty_cd, ZSUNIT(tp->t_dev));
   1336 	struct zs_chanstate *cs = zst->zst_cs;
   1337 	int s;
   1338 
   1339 	if (cs->cs_wr5_rts == 0)
   1340 		return (0);
   1341 
   1342 	s = splzs();
   1343 	if (block) {
   1344 		if (!ISSET(zst->zst_rx_flags, RX_TTY_BLOCKED)) {
   1345 			SET(zst->zst_rx_flags, RX_TTY_BLOCKED);
   1346 			zs_hwiflow(zst);
   1347 		}
   1348 	} else {
   1349 		if (ISSET(zst->zst_rx_flags, RX_TTY_OVERFLOWED)) {
   1350 			CLR(zst->zst_rx_flags, RX_TTY_OVERFLOWED);
   1351 			zst->zst_rx_ready = 1;
   1352 			cs->cs_softreq = 1;
   1353 		}
   1354 		if (ISSET(zst->zst_rx_flags, RX_TTY_BLOCKED)) {
   1355 			CLR(zst->zst_rx_flags, RX_TTY_BLOCKED);
   1356 			zs_hwiflow(zst);
   1357 		}
   1358 	}
   1359 	splx(s);
   1360 	return (1);
   1361 }
   1362 
   1363 /*
   1364  * Internal version of zshwiflow
   1365  * called at splzs
   1366  */
   1367 static void
   1368 zs_hwiflow(zst)
   1369 	struct zstty_softc *zst;
   1370 {
   1371 	struct zs_chanstate *cs = zst->zst_cs, *ccs;
   1372 
   1373 	if (cs->cs_wr5_rts == 0)
   1374 		return;
   1375 
   1376 	ccs = (cs->cs_ctl_chan != NULL ? cs->cs_ctl_chan : cs);
   1377 
   1378 	if (ISSET(zst->zst_rx_flags, RX_ANY_BLOCK)) {
   1379 		CLR(ccs->cs_preg[5], cs->cs_wr5_rts);
   1380 		CLR(ccs->cs_creg[5], cs->cs_wr5_rts);
   1381 	} else {
   1382 		SET(ccs->cs_preg[5], cs->cs_wr5_rts);
   1383 		SET(ccs->cs_creg[5], cs->cs_wr5_rts);
   1384 	}
   1385 	zs_write_reg(ccs, 5, ccs->cs_creg[5]);
   1386 }
   1387 
   1388 
   1389 /****************************************************************
   1390  * Interface to the lower layer (zscc)
   1391  ****************************************************************/
   1392 
   1393 #define	integrate	static inline
   1394 integrate void zstty_rxsoft __P((struct zstty_softc *, struct tty *));
   1395 integrate void zstty_txsoft __P((struct zstty_softc *, struct tty *));
   1396 integrate void zstty_stsoft __P((struct zstty_softc *, struct tty *));
   1397 static void zstty_diag __P((void *));
   1398 
   1399 /*
   1400  * receiver ready interrupt.
   1401  * called at splzs
   1402  */
   1403 static void
   1404 zstty_rxint(cs)
   1405 	struct zs_chanstate *cs;
   1406 {
   1407 	struct zstty_softc *zst = cs->cs_private;
   1408 	u_char *put, *end;
   1409 	u_int cc;
   1410 	u_char rr0, rr1, c;
   1411 
   1412 	end = zst->zst_ebuf;
   1413 	put = zst->zst_rbput;
   1414 	cc = zst->zst_rbavail;
   1415 
   1416 	while (cc > 0) {
   1417 		/*
   1418 		 * First read the status, because reading the received char
   1419 		 * destroys the status of this char.
   1420 		 */
   1421 		rr1 = zs_read_reg(cs, 1);
   1422 		c = zs_read_data(cs);
   1423 
   1424 		if (ISSET(rr1, ZSRR1_FE | ZSRR1_DO | ZSRR1_PE)) {
   1425 			/* Clear the receive error. */
   1426 			zs_write_csr(cs, ZSWR0_RESET_ERRORS);
   1427 		}
   1428 
   1429 		cn_check_magic(zst->zst_tty->t_dev, c, zstty_cnm_state);
   1430 		put[0] = c;
   1431 		put[1] = rr1;
   1432 		put += 2;
   1433 		if (put >= end)
   1434 			put = zst->zst_rbuf;
   1435 		cc--;
   1436 
   1437 		rr0 = zs_read_csr(cs);
   1438 		if (!ISSET(rr0, ZSRR0_RX_READY))
   1439 			break;
   1440 	}
   1441 
   1442 	/*
   1443 	 * Current string of incoming characters ended because
   1444 	 * no more data was available or we ran out of space.
   1445 	 * Schedule a receive event if any data was received.
   1446 	 * If we're out of space, turn off receive interrupts.
   1447 	 */
   1448 	zst->zst_rbput = put;
   1449 	zst->zst_rbavail = cc;
   1450 	if (!ISSET(zst->zst_rx_flags, RX_TTY_OVERFLOWED)) {
   1451 		zst->zst_rx_ready = 1;
   1452 		cs->cs_softreq = 1;
   1453 	}
   1454 
   1455 	/*
   1456 	 * See if we are in danger of overflowing a buffer. If
   1457 	 * so, use hardware flow control to ease the pressure.
   1458 	 */
   1459 	if (!ISSET(zst->zst_rx_flags, RX_IBUF_BLOCKED) &&
   1460 	    cc < zst->zst_r_hiwat) {
   1461 		SET(zst->zst_rx_flags, RX_IBUF_BLOCKED);
   1462 		zs_hwiflow(zst);
   1463 	}
   1464 
   1465 	/*
   1466 	 * If we're out of space, disable receive interrupts
   1467 	 * until the queue has drained a bit.
   1468 	 */
   1469 	if (!cc) {
   1470 		SET(zst->zst_rx_flags, RX_IBUF_OVERFLOWED);
   1471 		CLR(cs->cs_preg[1], ZSWR1_RIE);
   1472 		cs->cs_creg[1] = cs->cs_preg[1];
   1473 		zs_write_reg(cs, 1, cs->cs_creg[1]);
   1474 	}
   1475 
   1476 #if 0
   1477 	printf("%xH%04d\n", zst->zst_rx_flags, zst->zst_rbavail);
   1478 #endif
   1479 }
   1480 
   1481 /*
   1482  * transmitter ready interrupt.  (splzs)
   1483  */
   1484 static void
   1485 zstty_txint(cs)
   1486 	struct zs_chanstate *cs;
   1487 {
   1488 	struct zstty_softc *zst = cs->cs_private;
   1489 
   1490 	/*
   1491 	 * If we've delayed a parameter change, do it now, and restart
   1492 	 * output.
   1493 	 */
   1494 	if (cs->cs_heldchange) {
   1495 		zs_loadchannelregs(cs);
   1496 		cs->cs_heldchange = 0;
   1497 		zst->zst_tbc = zst->zst_heldtbc;
   1498 		zst->zst_heldtbc = 0;
   1499 	}
   1500 
   1501 	/* Output the next character in the buffer, if any. */
   1502 	if (zst->zst_tbc > 0) {
   1503 		zs_write_data(cs, *zst->zst_tba);
   1504 		zst->zst_tbc--;
   1505 		zst->zst_tba++;
   1506 	} else {
   1507 		/* Disable transmit completion interrupts if necessary. */
   1508 		if (ISSET(cs->cs_preg[1], ZSWR1_TIE)) {
   1509 			CLR(cs->cs_preg[1], ZSWR1_TIE);
   1510 			cs->cs_creg[1] = cs->cs_preg[1];
   1511 			zs_write_reg(cs, 1, cs->cs_creg[1]);
   1512 		}
   1513 		if (zst->zst_tx_busy) {
   1514 			zst->zst_tx_busy = 0;
   1515 			zst->zst_tx_done = 1;
   1516 			cs->cs_softreq = 1;
   1517 		}
   1518 	}
   1519 }
   1520 
   1521 /*
   1522  * status change interrupt.  (splzs)
   1523  */
   1524 static void
   1525 zstty_stint(cs, force)
   1526 	struct zs_chanstate *cs;
   1527 	int force;
   1528 {
   1529 	struct zstty_softc *zst = cs->cs_private;
   1530 	u_char rr0, delta;
   1531 
   1532 	rr0 = zs_read_csr(cs);
   1533 	zs_write_csr(cs, ZSWR0_RESET_STATUS);
   1534 
   1535 	/*
   1536 	 * Check here for console break, so that we can abort
   1537 	 * even when interrupts are locking up the machine.
   1538 	 */
   1539 	if (ISSET(rr0, ZSRR0_BREAK))
   1540 		cn_check_magic(zst->zst_tty->t_dev, CNC_BREAK, zstty_cnm_state);
   1541 
   1542 	if (!force)
   1543 		delta = rr0 ^ cs->cs_rr0;
   1544 	else
   1545 		delta = cs->cs_rr0_mask;
   1546 	cs->cs_rr0 = rr0;
   1547 
   1548 	if (ISSET(delta, cs->cs_rr0_mask)) {
   1549 		SET(cs->cs_rr0_delta, delta);
   1550 
   1551 		/*
   1552 		 * Pulse-per-second clock signal on edge of DCD?
   1553 		 */
   1554 		if (ISSET(delta, zst->zst_ppsmask)) {
   1555 			struct timeval tv;
   1556 			if (ISSET(rr0, zst->zst_ppsmask) == zst->zst_ppsassert) {
   1557 				/* XXX nanotime() */
   1558 				microtime(&tv);
   1559 				TIMEVAL_TO_TIMESPEC(&tv,
   1560 					&zst->ppsinfo.assert_timestamp);
   1561 				if (zst->ppsparam.mode & PPS_OFFSETASSERT) {
   1562 					timespecadd(&zst->ppsinfo.assert_timestamp,
   1563 					    &zst->ppsparam.assert_offset,
   1564 					    &zst->ppsinfo.assert_timestamp);
   1565 				}
   1566 
   1567 #ifdef PPS_SYNC
   1568 				if (zst->ppsparam.mode & PPS_HARDPPSONASSERT)
   1569 					hardpps(&tv, tv.tv_usec);
   1570 #endif
   1571 				zst->ppsinfo.assert_sequence++;
   1572 				zst->ppsinfo.current_mode = zst->ppsparam.mode;
   1573 			} else if (ISSET(rr0, zst->zst_ppsmask) ==
   1574 						zst->zst_ppsclear) {
   1575 				/* XXX nanotime() */
   1576 				microtime(&tv);
   1577 				TIMEVAL_TO_TIMESPEC(&tv,
   1578 					&zst->ppsinfo.clear_timestamp);
   1579 				if (zst->ppsparam.mode & PPS_OFFSETCLEAR) {
   1580 					timespecadd(&zst->ppsinfo.clear_timestamp,
   1581 						&zst->ppsparam.clear_offset,
   1582 						&zst->ppsinfo.clear_timestamp);
   1583 				}
   1584 
   1585 #ifdef PPS_SYNC
   1586 				if (zst->ppsparam.mode & PPS_HARDPPSONCLEAR)
   1587 					hardpps(&tv, tv.tv_usec);
   1588 #endif
   1589 				zst->ppsinfo.clear_sequence++;
   1590 				zst->ppsinfo.current_mode = zst->ppsparam.mode;
   1591 			}
   1592 		}
   1593 
   1594 		/*
   1595 		 * Stop output immediately if we lose the output
   1596 		 * flow control signal or carrier detect.
   1597 		 */
   1598 		if (ISSET(~rr0, cs->cs_rr0_mask)) {
   1599 			zst->zst_tbc = 0;
   1600 			zst->zst_heldtbc = 0;
   1601 		}
   1602 
   1603 		zst->zst_st_check = 1;
   1604 		cs->cs_softreq = 1;
   1605 	}
   1606 }
   1607 
   1608 void
   1609 zstty_diag(arg)
   1610 	void *arg;
   1611 {
   1612 	struct zstty_softc *zst = arg;
   1613 	int overflows, floods;
   1614 	int s;
   1615 
   1616 	s = splzs();
   1617 	overflows = zst->zst_overflows;
   1618 	zst->zst_overflows = 0;
   1619 	floods = zst->zst_floods;
   1620 	zst->zst_floods = 0;
   1621 	zst->zst_errors = 0;
   1622 	splx(s);
   1623 
   1624 	log(LOG_WARNING, "%s: %d silo overflow%s, %d ibuf flood%s\n",
   1625 	    zst->zst_dev.dv_xname,
   1626 	    overflows, overflows == 1 ? "" : "s",
   1627 	    floods, floods == 1 ? "" : "s");
   1628 }
   1629 
   1630 integrate void
   1631 zstty_rxsoft(zst, tp)
   1632 	struct zstty_softc *zst;
   1633 	struct tty *tp;
   1634 {
   1635 	struct zs_chanstate *cs = zst->zst_cs;
   1636 	int (*rint) __P((int c, struct tty *tp)) = tp->t_linesw->l_rint;
   1637 	u_char *get, *end;
   1638 	u_int cc, scc;
   1639 	u_char rr1;
   1640 	int code;
   1641 	int s;
   1642 
   1643 	end = zst->zst_ebuf;
   1644 	get = zst->zst_rbget;
   1645 	scc = cc = zstty_rbuf_size - zst->zst_rbavail;
   1646 
   1647 	if (cc == zstty_rbuf_size) {
   1648 		zst->zst_floods++;
   1649 		if (zst->zst_errors++ == 0)
   1650 			callout_reset(&zst->zst_diag_ch, 60 * hz,
   1651 			    zstty_diag, zst);
   1652 	}
   1653 
   1654 	/* If not yet open, drop the entire buffer content here */
   1655 	if (!ISSET(tp->t_state, TS_ISOPEN)) {
   1656 		get += cc << 1;
   1657 		if (get >= end)
   1658 			get -= zstty_rbuf_size << 1;
   1659 		cc = 0;
   1660 	}
   1661 	while (cc) {
   1662 		code = get[0];
   1663 		rr1 = get[1];
   1664 		if (ISSET(rr1, ZSRR1_DO | ZSRR1_FE | ZSRR1_PE)) {
   1665 			if (ISSET(rr1, ZSRR1_DO)) {
   1666 				zst->zst_overflows++;
   1667 				if (zst->zst_errors++ == 0)
   1668 					callout_reset(&zst->zst_diag_ch,
   1669 					    60 * hz, zstty_diag, zst);
   1670 			}
   1671 			if (ISSET(rr1, ZSRR1_FE))
   1672 				SET(code, TTY_FE);
   1673 			if (ISSET(rr1, ZSRR1_PE))
   1674 				SET(code, TTY_PE);
   1675 		}
   1676 		if ((*rint)(code, tp) == -1) {
   1677 			/*
   1678 			 * The line discipline's buffer is out of space.
   1679 			 */
   1680 			if (!ISSET(zst->zst_rx_flags, RX_TTY_BLOCKED)) {
   1681 				/*
   1682 				 * We're either not using flow control, or the
   1683 				 * line discipline didn't tell us to block for
   1684 				 * some reason.  Either way, we have no way to
   1685 				 * know when there's more space available, so
   1686 				 * just drop the rest of the data.
   1687 				 */
   1688 				get += cc << 1;
   1689 				if (get >= end)
   1690 					get -= zstty_rbuf_size << 1;
   1691 				cc = 0;
   1692 			} else {
   1693 				/*
   1694 				 * Don't schedule any more receive processing
   1695 				 * until the line discipline tells us there's
   1696 				 * space available (through comhwiflow()).
   1697 				 * Leave the rest of the data in the input
   1698 				 * buffer.
   1699 				 */
   1700 				SET(zst->zst_rx_flags, RX_TTY_OVERFLOWED);
   1701 			}
   1702 			break;
   1703 		}
   1704 		get += 2;
   1705 		if (get >= end)
   1706 			get = zst->zst_rbuf;
   1707 		cc--;
   1708 	}
   1709 
   1710 	if (cc != scc) {
   1711 		zst->zst_rbget = get;
   1712 		s = splzs();
   1713 		cc = zst->zst_rbavail += scc - cc;
   1714 		/* Buffers should be ok again, release possible block. */
   1715 		if (cc >= zst->zst_r_lowat) {
   1716 			if (ISSET(zst->zst_rx_flags, RX_IBUF_OVERFLOWED)) {
   1717 				CLR(zst->zst_rx_flags, RX_IBUF_OVERFLOWED);
   1718 				SET(cs->cs_preg[1], ZSWR1_RIE);
   1719 				cs->cs_creg[1] = cs->cs_preg[1];
   1720 				zs_write_reg(cs, 1, cs->cs_creg[1]);
   1721 			}
   1722 			if (ISSET(zst->zst_rx_flags, RX_IBUF_BLOCKED)) {
   1723 				CLR(zst->zst_rx_flags, RX_IBUF_BLOCKED);
   1724 				zs_hwiflow(zst);
   1725 			}
   1726 		}
   1727 		splx(s);
   1728 	}
   1729 
   1730 #if 0
   1731 	printf("%xS%04d\n", zst->zst_rx_flags, zst->zst_rbavail);
   1732 #endif
   1733 }
   1734 
   1735 integrate void
   1736 zstty_txsoft(zst, tp)
   1737 	struct zstty_softc *zst;
   1738 	struct tty *tp;
   1739 {
   1740 
   1741 	CLR(tp->t_state, TS_BUSY);
   1742 	if (ISSET(tp->t_state, TS_FLUSH))
   1743 		CLR(tp->t_state, TS_FLUSH);
   1744 	else
   1745 		ndflush(&tp->t_outq, (int)(zst->zst_tba - tp->t_outq.c_cf));
   1746 	(*tp->t_linesw->l_start)(tp);
   1747 }
   1748 
   1749 integrate void
   1750 zstty_stsoft(zst, tp)
   1751 	struct zstty_softc *zst;
   1752 	struct tty *tp;
   1753 {
   1754 	struct zs_chanstate *cs = zst->zst_cs;
   1755 	u_char rr0, delta;
   1756 	int s;
   1757 
   1758 	s = splzs();
   1759 	rr0 = cs->cs_rr0;
   1760 	delta = cs->cs_rr0_delta;
   1761 	cs->cs_rr0_delta = 0;
   1762 	splx(s);
   1763 
   1764 	if (ISSET(delta, cs->cs_rr0_dcd)) {
   1765 		/*
   1766 		 * Inform the tty layer that carrier detect changed.
   1767 		 */
   1768 		(void) (*tp->t_linesw->l_modem)(tp, ISSET(rr0, ZSRR0_DCD));
   1769 	}
   1770 
   1771 	if (ISSET(delta, cs->cs_rr0_cts)) {
   1772 		/* Block or unblock output according to flow control. */
   1773 		if (ISSET(rr0, cs->cs_rr0_cts)) {
   1774 			zst->zst_tx_stopped = 0;
   1775 			(*tp->t_linesw->l_start)(tp);
   1776 		} else {
   1777 			zst->zst_tx_stopped = 1;
   1778 		}
   1779 	}
   1780 }
   1781 
   1782 /*
   1783  * Software interrupt.  Called at zssoft
   1784  *
   1785  * The main job to be done here is to empty the input ring
   1786  * by passing its contents up to the tty layer.  The ring is
   1787  * always emptied during this operation, therefore the ring
   1788  * must not be larger than the space after "high water" in
   1789  * the tty layer, or the tty layer might drop our input.
   1790  *
   1791  * Note: an "input blockage" condition is assumed to exist if
   1792  * EITHER the TS_TBLOCK flag or zst_rx_blocked flag is set.
   1793  */
   1794 static void
   1795 zstty_softint(cs)
   1796 	struct zs_chanstate *cs;
   1797 {
   1798 	struct zstty_softc *zst = cs->cs_private;
   1799 	struct tty *tp = zst->zst_tty;
   1800 	int s;
   1801 
   1802 	s = spltty();
   1803 
   1804 	if (zst->zst_rx_ready) {
   1805 		zst->zst_rx_ready = 0;
   1806 		zstty_rxsoft(zst, tp);
   1807 	}
   1808 
   1809 	if (zst->zst_st_check) {
   1810 		zst->zst_st_check = 0;
   1811 		zstty_stsoft(zst, tp);
   1812 	}
   1813 
   1814 	if (zst->zst_tx_done) {
   1815 		zst->zst_tx_done = 0;
   1816 		zstty_txsoft(zst, tp);
   1817 	}
   1818 
   1819 	splx(s);
   1820 }
   1821 
   1822 struct zsops zsops_tty = {
   1823 	zstty_rxint,	/* receive char available */
   1824 	zstty_stint,	/* external/status */
   1825 	zstty_txint,	/* xmit buffer empty */
   1826 	zstty_softint,	/* process software interrupt */
   1827 };
   1828